Personality differences between insomniac and non-insomniac psychiatry outpatients

The relationship between self-reported measures of sleep disturbance and psychopathology was investigated. Previous studies on this topic have failed to use appropriate control groups. The current study examined the relationship between sleep disturbance and personality using insomniac and non-insomniac outpatient counseling clients. The results confirm the significant and positive relation between emotional disturbance and insomnia. The insomniac group showed the expected pattern of MMPI abnormalities (elevated D, Hy, Pt and Sc). However, only the Pt scale of the MMPI and the Cornell Medical Index significantly differentiated the two groups. This suggests that characteristics such as obsessional worry which lead to elevated Pt scores play a more important and unique role in insomnia than previously hypothesized.